Quiescent Prominence Equilibria

Abstract

With a new analytical method, we present a static model for quiescent solar prominences of inverse polarity. These prominences have a plasma β slightly below unity and correspond to those located in the lower corona. Although this static model cannot address the helmet-like features at the top of the prominences, which are believed to be associated with the open-field topology and driven by outflows, the model may nevertheless capture several characteristic features of the solar prominences. These features include the sheetlike gas condensation hanging above an asymptotically weak magnetic cusp, the sheared magnetic arcades/loops, the coronal cavity, radio dark strips cospatial with the Hα filaments, bright radio ribbons located on both sides of the dense prominence sheet, and the increasing magnetic field strength with height along the prominence sheet. In our model, the densest gas is contained within a narrow field-free tube immediately above the prominence sheet. Thermally insulated by the surrounding strong fields, this narrow tube may be a natural site for housing the cool gas (≥104 K) siphoned from the lower solar atmosphere. We also find that there are hot spots (≤107 K) located on the sides of the prominence loop, which might be the source of thermal X-ray emission in the quiet Sun.